Prior to the present invention, a valve arrangement of this general type has been taught in the prior art. See, for example, German publication DE No. 22 24 180 B2. This publication describes a solenoid-controlled inlet valve, indicated as 2, and a solenoid-controlled outlet valve, indicated as 3. The inlet valve 2 is closed by energizing the magnet, indicated as 12, of such solenoid-controlled inlet valve 2, and the solenoid-controlled outlet valve 3 is opened by energizing its solenoid magnet, indicated as 13. In this prior art arrangement, the solenoid-controlled inlet valve 2 opens and the solenoid-controlled outlet valve 3 closes in the pressurizing position, thus solenoid magnets 12 and 13 are deenergized. In the pressure-holding position, however, both the solenoid-controlled inlet valve 2 and the solenoid-controlled outlet valve 3 are closed. Therefore, the first solenoid magnet 12 is energized. On the other hand, in the pressure-release position of this prior art valve arrangement, the inlet valve 2 is closed and the outlet valve 3 is open. In this case, both valve solenoid magnets 12 and 13 are energized at the same point in time.
In contrast to the present invention, the above-described simultaneous energizing of both solenoid magnets 12 and 13, as required in this valve arrangement in the pressure-release position, and the corresponding doubling of the power requirement constitutes a significant disadvantage.